Or he could have gone from London to New York, Atlanta, Los Angeles, etc. and then to Dallas.
True. Depends on cash and if there were any layovers he wanted for sight seeing.
When we flew back and forth though, we took the flight path with the fewest hops. It’s a long, exhausting trip and you don’t need any more drama with hops than is necessary.
Imagine if he flew in to NYC for a few days to see friends or do a bit of touristing and then from NYC while symptomatic. EWR and La Guardia would be great spreaders.